Reforming technologies play a key role in the potential utilization of hydrocarbons in distributed applications for electricity generation. Specifically there is a need in the art for reforming technologies capable of hydrocarbon and/or biofuel oxidations to provide either hydrogen, small molecular weight carbon fragments (e.g. carbon oxides and methane) and/or small molecular weight alcohols, which can subsequently be utilized within a fuel cell for efficient, distributed electricity generation. Biofuels are various biomass derived fuels with a general chemical formula of CxHyOz.
In one application solid oxide fuel cells (SOFCs) using a direct feed of Jet-A fuel and/or biofuels are of interest as replacements for the gas turbine auxiliary power unit (APU) employed on commercial airplanes. Similar hydrocarbon and/or biofuel feeds could be used for SOFCs providing power to airport ground transportation. In a third application the use of fuel cells in automotive applications would require a direct feed of gasoline, diesel and/or biofuels.
For SOFCs the reforming catalyst can act as the anode of the fuel cell. The fuel cell anode directly (1) reforms the hydrocarbon and/or biofuel feeds to hydrogen, small carbon fragments (e.g., carbon oxides or methane) and/or small oxygenated hydrocarbons which are electrochemically oxidized at the anode to generate electricity; and/or (2) directly oxidize the hydrocarbon and/or biofuel feeds to water and carbon dioxide to generate electricity.
One example of a need for distributed electricity generation is the aircraft industry. The aircraft industry has seen interest in substituting electrically driven systems for hydraulically and pneumatically driven systems. However, such substitutions increase the electrical power requirements of aircraft.
Aircraft typically employ combustion-type auxiliary power units to provide electrical power to various electronic systems, such as navigation systems and the like. For example, commercial aircraft typically employ gas turbine auxiliary power units to supply the aircraft with auxiliary power. However, combustion-type auxiliary power units, such as gas turbine units, are known to have relatively low thermodynamic efficiencies and therefore consume significant amounts of the aircraft's aviation fuel supply. Furthermore, the weight of combustion-type auxiliary power units, as well as the extensive wiring associated with such units, significantly contribute to the overall weight of the aircraft, thereby further decreasing the aircraft's fuel efficiency.
Growing concerns over the use of fossil fuels have led commercial aircraft designers and manufacturers to explore new techniques for increasing the efficiency of combustion-type auxiliary power units, as well as alternative sources of auxiliary power. One alternative to using combustion-type auxiliary power units is to use fuel cells. Fuel cells generally have higher thermodynamic efficiencies and weigh significantly less than combustion-type auxiliary power units. Therefore, fuel cells offer the potential to supply the required auxiliary power while significantly reducing the consumption of fossil fuels.
Accordingly, those skilled in the art continue to seek advances in the use of reforming technologies for use within or in conjunction with fuel cells to provide sources of auxiliary power.